As his stature rises, Rubio becomes ripe target for rivals | Reuters

LACONIA, N.H. Marco Rubio finished third in Monday's Iowa caucuses, but his Republican White House rivals are attacking him as though he were the victor, and on Wednesday the U.S. senator from Florida peppered his speech with humble caveats that seemed designed to deflect the hits.

As the 2016 candidates looked ahead to Tuesday's New Hampshire primary, New Jersey Governor Chris Christie has called Rubio "the boy in the bubble," suggesting he gives the same speech no matter where he goes.

Senator Lindsey Graham of South Carolina, who is campaigning for former Florida Governor Jeb Bush, said Rubio could not win a general election because of his positions on abortion and immigration. Bush and Ohio Governor John Kasich both said the country needed an experienced commander in chief, in what appeared to be a jab at Rubio, a first-term senator.

In the run-up to the Iowa caucuses, Republicans Donald Trump and Ted Cruz, two anti-establishment candidates, had dominated the polls in the state while Rubio lagged well behind. But on Monday, he racked up a surprisingly strong third-place finish, garnering the support of 23 percent of Republican caucus goers, just below Trump's 24 percent second-place finish. Cruz, a senator from Texas, won Iowa with 28 percent. Many pundits had predicted Rubio would struggle to get much above 15 percent to 20 percent in the state.

Rubio struck a triumphant tone in his post-caucus speech. “This is the moment they said would never happen,” he said, adding that the people of Iowa had “sent a very clear message.”

On Wednesday, though, he gave a cautious outlook on his prospects in New Hampshire and beyond. Rubio said he was leaving his fate in the Republican U.S. presidential primary contests in God’s hands, and added that he hoped his children would be proud of him "no matter how this turns out."

“I just want to do as well as we possibly can here in New Hampshire," Rubio told reporters.

After emerging as the leading “establishment” candidate competing with Trump and Cruz, Rubio faces high stakes in New Hampshire. His elevated stature in the race has given his rivals added incentive to attack him.

Some voters in the state seemed to be warming to him.

Grace Freije, 63, of Bow, New Hampshire, said she had decided to support Rubio after gravitating earlier toward Christie. Steve McMahon, 65, said the same.

"He's not a divisive person," McMahon said. "This guy's got the best shot at winning."